Inborn Errors of Long Chain Fat Metabolism

长链脂肪代谢先天性错误

基本信息

批准号：
8047953
负责人：
GERARD VOCKLEY
金额：
$ 29.1万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-04-01 至 2012-06-14
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8047953
关键词：
Acute Liver Failure Acyl CoA Dehydrogenases Acyl Coenzyme A Affect Alternative Splicing Amino Acid Motifs Amino Acids Bile Acid Biosynthesis Pathway Bile Acids Biogenesis Cardiomyopathies Catabolism Cell Nucleus Cells Cessation of life Chemicals Chenodeoxycholic Acid Clinical Complex Data Defect Development Disease Enzymes Equilibrium Esters Family Fatty Acids Fatty Liver Gene Family Generations Genes Genetic Genotype Goals Hereditary Disease Human Inborn Errors of Metabolism Inborn Genetic Diseases Inner mitochondrial membrane Knockout Mice Lead Learning Lecithin Length Lipids Liver Failure Location Long-Chain-Acyl-CoA Dehydrogenase Lung Metabolic Metabolic Pathway Metabolism Mitochondria Mitochondrial Matrix Molecular Molecular Conformation Mus Mutation Newborn Infant Pathway interactions Patients Pattern Phenotype Physiological Premature Infant Preparation Process Proteins Reye Syndrome Role Structure-Activity Relationship Substrate Specificity Tissues Variant acyl-CoA dehydrogenase base dehydrogenation enzyme deficiency fatty acid oxidation in vivo lipid metabolism member mouse model mutant novel oxidation surfactant

项目摘要

DESCRIPTION (provided by applicant): The acyl-CoA dehydrogenases (ACDs) are a family of multimeric flavoenzymes that catalyze the 1,2- dehydrogenation of acyl-CoA esters in fatty acid 2-oxidation and amino acid catabolism. Inborn errors of metabolism have been identified in seven of the ACDs. The long range objective of this project has been to investigate important structure/function relationships in the ACD gene family. We have described and characterized several new members of the ACD gene family. Among these are 3 enzymes with significant activities with long chain substrates: long and very long chain acyl-CoA dehydrogenases (LCAD and VLCAD, respectively), and ACD9 and. Our prior and preliminary studies show that these enzymes have distinct substrate utilization profiles, tissue and developmental expression patterns, exist in multiple active forms in the cell, and are present in multiple subcellular locations. The goal of this revised application is to characterize the physiologic roles of LCAD, VLCAD, and ACD9 and explore the ramifications of genetic deficiencies of these enzymes in humans and mouse models. Specific Aim 1 is to characterize variant forms of very long chain acyl-CoA dehydrogenase (VLCAD) and the molecular basis of clinical variability in this disorder. Specific aim 1a is to identify the amino acid motif(s) important in determining the unique localization of VLCAD to the inner mitochondrial membrane. Specific aim 1b is to characterize alternative forms of VLCAD identified in vivo. We have identified 3 variant forms of this enzyme in vivo that are generated through alternative splicing. I hypothesize that each has a different substrate specificity that provides functional optimization for progressively shorter substrate species. Specific aim 1c is to characterize the effect of patient mutations in VLCAD on enzyme function. Specific Aim 2 is to more completely characterize ACD9 and its deficiency in humans. Specific Aim 2a is identification of additional patients with ACD9 deficiency and definition of its clinical spectrum. Specific Aim 2b is characterization of the subcellular distribution of ACD9 and the function and molecular configuration of ACD9 protein outside of mitochondria. I hypothesize that this alternative form of ACD9 has non-enzymatic "moonlighting" functions in the cell. Specific Aim 3 is to elucidate the physiologic function of LCAD. Despite its early recognition, its in vivo metabolic role remains a mystery. Our preliminary data implicates it in bile acid and surfactant metabolism. Specific Aim 3a is to characterize the role of LCAD in bile acid synthesis. I hypothesize that it characterizes a key intermediate step in chenodeoxycholic acid synthesis in a mitochondrial based acidic pathway that is involved in the control of cellular metabolic rate. Specific Aim 3b is to explore the role of LCAD in surfactant metabolism using an LCAD null mouse. These studies necessitate a fundamental revision in our view of mitochondrial 2-oxidation from a metabolic pathway that is only responsible for energy generation to one that is active as well in a variety of previously unrec- ognized functions in other important biologic processes.

描述（由申请人提供）：酰基-COA脱氢酶（ACD）是多聚酸黄酮酶的家族，可催化脂肪酸2-氧化和氨基酸分解代谢中酰基-COA酯的1,2-脱氢。在七个ACD中已经确定了新陈代谢的先天错误。该项目的远距离目标是研究ACD基因家族中重要的结构/功能关系。我们已经描述并描述了ACD基因家族的几个新成员。其中包括3种具有长链底物活性的酶：长链酰基-COA脱氢酶（分别为LCAD和VLCAD）和ACD9和。我们的先前和初步研究表明，这些酶具有不同的底物利用率，组织和发育表达模式，以多种活性形式存在于细胞中，并且存在于多个亚细胞位置。此修订应用的目的是表征LCAD，VLCAD和ACD9的生理作用，并探讨这些酶在人类和小鼠模型中这些酶的遗传缺陷的后果。具体目的1是表征非常长链酰基-COA脱氢酶（VLCAD）的变体形式和该疾病中临床变异性的分子基础。具体目的1a是确定在确定VLCAD内部线粒体膜独特定位至关重要的氨基酸基序。特定的目标1B是表征体内识别的VLCAD的替代形式。我们已经鉴定了通过替代剪接生成的3种这种酶的变体形式。我假设每个都有不同的底物特异性，可为逐渐较短的底物物种提供功能优化。具体目标1C是表征VLCAD中患者突变对酶功能的影响。具体目的2是更彻底地表征ACD9及其在人类中的缺乏。特定的目标2a是鉴定ACD9缺乏症的其他患者及其临床光谱的定义。特定的目标2b是ACD9亚细胞分布的表征以及线粒体以外的ACD9蛋白的功能和分子构型。我假设这种替代形式的ACD9在细胞中具有非酶“月光”功能。具体目标3是阐明LCAD的生理功能。尽管早期认可，但其体内代谢角色仍然是一个谜。我们的初步数据将其与胆汁酸和表面活性剂代谢有关。特定目标3a是表征LCAD在胆汁酸合成中的作用。我假设它是在基于线粒体的酸性途径中涉及细胞代谢速率的基于线粒体的酸性途径中氯二胆酸合成的关键中间步骤。特定的目标3B是使用LCAD null小鼠探索LCAD在表面活性剂代谢中的作用。这些研究需要从代谢途径的线粒体2-氧化的观点中进行基本修订，该途径仅负责能量产生到活性的能量发电途径，以及在其他重要的生物学过程中的各种以前未经认可的功能中。